|Pearl Price Factors|
Drill hole test: Look inside the drill hole with magnifier. Cultured pearls have a dark dividing line separating the nacre from a pearl bead nucleus. The dark line is the material called conchiolin which binds the nacre to the bead. While natural pearls have a series of growth lines that get more yellow or brown towards the center of the pearl. And for white pearls, if there is a black deposit at the center of them, they must be sured to be natural. What's more, some natural pearls are valued by weight. Nevertheless, natural pearls drill holes are often smaller than 0.04mm(0.016 inch) to minimize weight loss, while the drill holes of cultured pearls tend to 0.06mm(0.024inch).
Blink test: Hold the strand near the front edge of a strong lamp and rotate the strand. If the pearls blink from light to dark as they are turned, they are cultured.
Stripe test: When you rotate the pearls with strong light shining through them, look for curved lines and stripes. These are the growth layers of the shell beads. If they are visible and the nacre is very thin, the pearls are cultured. And keep in mind that imitation pearls with shell-bead centers can display this banded effect, too. However, natural pearls will not look striped.
Color test: Cultured pearls often have a faint greenish tint, while natural pearls is at the presence of overtone, even orient. The color of natural pearls has a greater potential for brightness than that of cultured pearls. And color is just a suggestion to determine a pearl might be cultured.
Shape test: If the pearls look perfectly round, they are likely to be cultured. Natural pearls tend to be at least slightly irregular shapes. This test is also only an indication.
Matching test: Because of the rarity, it is not so easy to find natural pearls which are matched. That is to say, natural pearls do not appear as well matched for color, shape, size and luster as cultured pearls.